Orifice meter



Dec. l0, 1935. w, H. PARKER Er AL ORIFICE METER Filed March 4, 1930 All@' WMM@ @www Dec. 10, 1935. Iw. H. PARKER Er A1. 2,024,059

ORIFICE METER Filed March 4, 1930 4 Sheets-Sheet 2 Dec. 10, 1935. w HPARKER "ET AL 2,024,059

ORIFICE METER Filed March 4, 1930 4 Sheets-Sheet 3 Dec 10, 1935- w. H.PARKER ET AL 2,024,059

ORIFICE METER Filed Maron 4, i930 4 sheets-sheet 4 :Ime/Miou;

Patented Dec. l0, 1935 UNITED STATES PATENT OFFICE omFIcE METERPennsylvania Application March 4, 1930, Serial No. 433,110

17 Claims.

This invention relates to new and useful improvements in orifice metersused for measuring the flow of gases or liquids.

In the usual type of orifice meter there is a restriction in a. conduitthrough which the fluid passes, with pipes connected to the high and lowpressure sides of said restriction, said pipes being connected to highand low pressure chambers of the meter, the chambers being joined by a Utube containing liquid. One of said chambers, usually the high pressurechamber, has a float therein, the movement of which indicates thedifferential pressure and therefore the ow of fluid. The float isusually connected to a pivoted pen arm or other indicator, whereby saidarm is operated about its pivot in response to vertical movement of thefloat.

An object of this invention isthe provision in an orifice meter of amechanism for transmitting the movement of the float to an indicatorwhich eliminates the use of a stuffing box and reduces friction. f

Another object is the provision of an indicator operating shaft which issealed by lubricant to prevent loss of pressure from the oat chamber ofthe meter.

Another object of this invention is to provide an orifice meter having adamping valve and a draining vent adjacent thereto so that it can becleaned with a minimum of labor.

A further object is the provision of means for preventing over or underranging of the orice meter upon sudden changes of pressure of the iiuidbeing measured.

Another object of this invention is to provide an orifice meter soconstructed that it may be readily disassembled for cleaning and may bereadily reassembled after the cleaning operation to its originalsetting, so that recalibration is not required.

Another object of this invention is to provide a novel manifoldstructure integrally constructed and having all joints thereof securelyxed, as by welding, soldering or the like, and provided with a pluralityof valves for testing and checking, thus eliminating the possibility ofleakage caused by loosening of the joints during shipment and duringinstallation and operation.

Another object of this invention is to provide an orifice meter havinginterchangeable chambers so that its 'differential range may be readilychanged from 20 inches to 50 inches or 100 inches or to any othersuitable range. The interchangeable parts whereby the above changeovermay be accomplished are greatly simplified such that by the removal offour screws and one union nut the change from one capacity meter to theother may be made.

These and other objects will be apparent from the following description'and the appended claims when taken in conjunction with the accompanyingdrawings wherein:

Figure 1 is a. rear view of our orifice meter with parts thereof insection, and the pipes disconnected therefrom.

Figure 2 is a front elevation thereof on a smaller scale.

Figure 3 is a side elevation thereof.

Figure 4 is a top plan of the valves manifold for checking and testing.

Figure 5 is a longitudinal section thereof with one pipe connectedthereto.

Figure 6 is a sectional view of one of the valves used with themanifold.

Figure 7 is an enlarged view from above partly in section showing thelinkage connecting the float arm and the pen shaft.

Fifiure 8 is a detail sectional view taken on line 8 8 of Figure 7.

Figure 9 is a view similar to Fgiure 'l showing a modified form.

Figure 10 is a broken sectional view of the twenty inch chamber and theadapter for connecting it to the meter.

Figure 11 is an enlarged section on line I I-Il of Figure 1 showing thecombined damping device and drain valve.

Figure 12 is a plan of the float arm link.

Figure 13 is a plan of the pen link.

Figure 14 is a plan of the pen link take-up arm.

Figure 15 is an end elevation thereof.

Figures 16, 17 and 18 are front, side and rear elevations, respectively,of the oat arm link hub used for adjustments.

Figure 19 is a diagrammatic view showing the movement of thecompensating links.

Referring to the drawings (Fig. 2) the conduit l is provided with arestriction 2 which may be a plate within said conduit or a Venturitube, the pipe 3 being connected to the low pressure side of therestriction, and pipe 4 being connected to the high pressure sidethereof. The low pressure pipe 3 passes by means of valve 5 and unioncoupling 6 into communication with an upwardly extending conduit 1 of aunitary manifold structure which has on one end thereof a union coupling8 for threaded engagement with the low pressure chamber of the meter.

The high pressure pipe 4 is connected to valve 9 and union coupling l2into communication with bypass pipe I3 of the .manifold having a branchI4 for connection with the high pressure chamber of the meter by meansof a screwthreaded coupling I5.

A novel device is interposed between the pipes 1 and I3 in order tozero, check, and test the orifice meter under service conditions. Thisdevice comprises a main body I6 which is securely fixed to the pipes 1and I3, as by welding, brazing or soldering, to form therewith a.unitary manifold construction. This manifold device is shown in detailin Figures 4 and 5. The main body I6 has three ports I1 therein for thereception of valves I8, I9, and 22. A cross channel 23 extendslengthwise of the manifold body I6, 'saidI channel communicating withthe openings I1. Each opening I1 has a bore 24 communicating with thebottom thereof, the bore I1 at the lower end of manifold I6 in which ispositioned valve I8 having a connecting channel 25 communicatingtherewith and connected to a chamber 26.

The pipe I3 is secured in chamber 26 as by welding, the pipe I3 thuscommunicating with channel 25. The bore 24 for the central opening I1communicates with a screw ythreaded socket 21.adapted to receive apressure gauge.' The opening I1 at the upper end of the manifold is incommunication with a semi-cylindrical channel 28, by means of a bore 29communicating with the bore 24 in the bottom of the upper chamber I1.The semi-cylindrical channel 28 is adapted to receive pipe 1 and issecurely fixed thereto as by welding. Pipe 1 has a channel 30 therein tothus place pipe 1 in communication with bore 29, upper bore 24, andopening I1.

The needle valves I8, I9 and 22 control passage of fluid from bores 24into the respective openings I1, to thus control passage of fluidthrough longitudinal channel 23. By closing the needle valves I8 and 22communication between pipes 1 and I3 through the main body I6 is cut osince valve I8 closes the channel 25 and valve 22 closes the channel 29at the upper end of the manifold.

In order to zero the orifice meter, or to put equal pressure in both thehigh and low pressure chambers thereof, the center valve I9 is closedand the end valves I8 and 22 are opened. Thus communication isestablished between the high pressure pipe I3 and the low pressure pipe'I by means of the lower opening 26 in the manifold, the bore 25, bore24 of the lower valve I 8, channel 23, upper bore 24, and channel 29 toopening 30 into pipe 1. The communication thus established will cause abalance of pressurein both the high and low pressure chambers of themeter since the pressure is by-passed around the orifice meter and thelevel of liquid in the two pressure chambers will be the same so thatthe instrument will indicate zero diierential pressure and can be socalibrated.

The orifice meter can be checked by closing either one of valves I8 or22 so that the orifice meter records the gauge pressure in the line. Byconnecting an accurate pressure gauge at opening 21 the gauge likewisewill register the gauge pressure in the line, and the readings of theoriiice meter pen and gauge can be compared to check the accuracy of theorifice meter. test the low static pressure in the conduit, the lowervalve I8 is closed and the center valve I9 and the upper valve 22 areopened. If desired the high static pressure may also be' tested on thepressure gauge by opening lower valve I8 and center valve I9, andclosing upper valve 22.

It will be clear that the manifold construction as above described is somade that with the needle valves associated therewith pressure can beshunted across the manifold or pressure from either side can be readfrom a pressure gauge 5 connected therewith. The valves 5 and 9 in thelow and high pressure pipes 3 and 4 are provided so that pressure fromeither or both sides may be shut off. The manifold body construction asabove described, welded or otherwise fix- 10 edly secured to pipes 1 andI3 makes a compact and rigid construction. By making the manifold bodyI6 in one piece all joints and possibility of leakage are eliminated.The manifold will stand up under rough treatment and can be 15 twistedand sprung into place between the conduits when necessary without anytendency to loosen any threaded pipe joints, as would be the case ifthreaded joints were used.

It will be understood that this invention is associated with an orificemeter embodying a chart whereon is recorded the differential pressure asindicated by the position of the float and the static low pressure. Inorder to impress the static low pressure on the static indicating means25 associated with the orifice meter, the manifold construction includesa pipe 32 which is branched from pipe 1 and has a threaded coupling 33thereon for engagement with the conduit of the meter leading to thestatic pressure gauge, not 30 shown.

'Ihe needle valves, I8, I9 and 22 are duplicates and one only will bedescribed. As seen in Fig.

6 each valve includes a threaded bushing 35 for reception in thethreaded opening I1 of the man- 35 ifold body, said bushings beinginteriorly threaded for the reception of the reciprocating valve member38, having a conical valve 31 thereon, and provided with a handle 3.8. Apacking nut 39-is threaded on boss 35 to compress the pack- 40 ing 42into uid tight engagement with the valvev stem. By rotation of handle 38it will be clear that the valve 31 may be seated on or moved away fromthe end of the bore 24 to close or open these passages. 45

Referring now to Figure 1 wherein is shown an enlarged view of the rearface of the oriiice meter, parts thereof being shown in section, a maincasting 43 is secured to the back of the meter casing 44 in which iscontained the clock, the 50 pressure element and pressure indicatingpen, and the differential pressure indicating or pen arm.

Casting 43 has a lower flange 45 to which is secured the float chamber46 containing the iioat 55 41 having secured thereto the iioat arm 48.Float arm 48 projects upwardly through a restricted opening 49 in theange 45, there being secured to the lower face of flange 45 around saidopening a suitable composition valve seat 52 for 60 cooperativeengagement by a convex valve member 53 on the upper end of float 41,whereby if the device is subjected to excessive pressure the float 41will rise and the valve 53 thereon will engage'on seat 52 to preventloss of the liquid, such 65 as mercury through the opening 49.

The float chamber 46 has a downwardly projecting nipple 54 to which isscrew threaded a coupling member 55. A lower valve seat 56 is clampedagainst the nipple 54 by screw-threaded 70 coupling 55 and serves toseal the connection, and float 41 has a depending stem 58 to which issecured a valve 59 for cooperation with seat 56. Valve 59 is looselypivoted to stemI 58 such that it may move freely in all directions tohave a lim- 75 ited universal motion whereby it may accurately y seatagainst valve seat 56. Thus it will be seen that excessive high pressureor excessive low pressure will not result in the loss of mercury sinceeither valve 53 will close on seat 52 or valve 59 will close on seat 56to prevent loss of mercury from the U tube associated with the orificemeter.

A depending pipe 62 is secured in liquid tight engagement to nipple 54by coupling 55, said pipe 62 having a guide bushing 63 therein forguiding rod 64 secured to the lower part of valve 59, and thus securedto oat 41. By the provision of bushing 63, and guide rod 64, the float41 is so guided that its motion is vertical.

A U tube 65 is secured to the lower end of conduit 62 as by welding orotherwise and is secured at its other end to chamber 66, as by welding.As .shown in full lines in Fig. 1 chamber 66 is flanged at 61 and issecured at its upper end to flange 45 of casting 43 by bolts not shown,which connect these two flanges. The ange 45 is bored as at 68, saidbore 68 being provided at its end with a threaded portion 69 forconnection with threaded nipple |5 leading from the high pressure sideof the conduit. A threaded bore 12 is provided in casting 43 for thereception of threaded coupling 8, whereby low pressure from the conduitis put into communication with the main chamber of casting 43 and by wayof opening 49 into the low pressure chamber 46.

In order that the orifice meter may be adapted for various ranges ofpressure, the high pressure chamber is made interchangeable with otherchambers which are adapted to fit upon the lower face of flange 45. Thehigh pressure chamber 66 shown in Fig. 1 is a one hundred inch chamber,that is, it is adapted to accommodate sufficient mercury to provideone-hundred inches of pressure of water corresponding approximately to3.61 pounds differential pressure. If it is desired to substitute achamber of different capacity such as a fifty inch chamber, the boltssecuring chamber 66 to flange 45 are removed and union 55 is unscrewed.

A shallower chamber adapted to fit against the ange 45 in a similarmanner to chamber 66 is then substituted, the new chamber having a Utube 65 welded thereto. Thus, the changing over of our improved orificemeter to various ranges is greatly simplified, since it is merelynecessary to remove four cap screws holding the chamber and unscrew oneunion, and then substitute the new range chamber.

If it is desired to use a 2'0 inch range chamber corresponding to a lowdifferential pressure, a shallow chamber 14 such as shown in Fig. 10 hasthe U tube 65 welded to the nipple 15 of said chamber 14, chamber 14being adapted to be secured to flange 45 by means of an adapter 11.Adaptern11 has an opening 18 therein for alignment with the opening inthe flange 45 and has openings for the reception of bolts for clampingthe same to the lower face of flange 45. The 20 inch chamber 14 issecured to the adapter 11 by bolts or other securing means.

By the above described interchangeability, a single orifice meter may beused to measure the ow of uid through pipes wherein the differentialpressure varies widely, since the low pressure chambers are readilyinterchangeable.

The oat arm 48 projects upwardly into the main casting 43 and terminatesin a conical end 82. In alignment with the float rod the casting 43 hasa threaded opening in the upper wall thereof adapted to receive a plug83, said plug having an extension 84 threaded for reception in theopening in casing 43, with a stop rod 85 projecting downwardly intocasing 43 and terminate ing in a conical seat 86. Plug 84 has anextension 5 81 extending in the opposite direction which is alsothreaded for engagement in opening in the casting 43. When the orificemeter is being shipped the plug 83 is screwed into the opening as shownin Fig. 1 until the conical end 86 there- 10 of engages with the end 82of float rod 48 to thus hold the movable parts of the instrument in setposition such that the mechanism can not be injured during shipment byrelative movement of the parts thereof. When the orifice meter is to 15be installed the plug 83 is removed from the opening in casting 43,turned over, and screwed back into said opening by means of the threadedportion 81, to prevent loss of pressure from the chamber. 'I'hus thesingle element 83 functions 20 as a stop, and also as a plug to preventloss or pressure. This is a feature of practical importance sinceneither the shipping stop nor the plug can be lost as one or the otheris always used, and this unitary member is therefore al- 25 Ways inplace.

A funnel shaped opening 88 is provided in communication with the lowpressure chamber 46, said opening being normally closed by a plug 89.When the plug 89 is removed mercury or other 30 liquid may be pouredinto the orifice meter for charging the U tube and the high and lowpressure chambers connected thereto.

In orifice meters of the type to which this invention relates thevertical movement of the float 36 operates an indicating arm or pen armto move an indicator over a scale in accordance with the verticalmovement of the float. However, due to the fact that the leveragebetween the vertically moving float and the indicator arm changes for 40various vertical positions of said float, it has been usual practice toprovide an indicating scale the divisions of which are madelproportionately larger for extreme positions of the float, or acompensating rod of varying cross-section areas 45 is used in chamber66. We have provided a novel mechanism connecting the vertically movingfloat arm and the indicator arm whereby the movements of the indicatorarms are in direct proportion to the movements of the float arm in .50all positions of the float.

A flattened portion 48 is providedon the float arm 48 adjacent the upperend thereof and a pin 92 passes through this flattened portion and issecurely fastened in opening 94 of a link or float 55 guide 93, saidlink being shown more fully in Fig. 13. At its opposite end said linkhas an enlarged opening 95 with two arcuate slots 96 concentrc withopening 95. The pin 92 passes through the link 93 and also through aslot 91 in a link 98, see 60 Figure 14.

The outer link 93 has mounted on its large end a dial |0| shown indetail in Figures 1'1, 18 and 19. Dial |0I has a concentric hub portion|02 adapted to fit snugly within the opening 95 of link 93. 65 Hub |02has an outstanding anlge member |03, of approximately the same diameteras the enlarged end of link 93. The flange |03 has openings 104 thereinfor the reception of screws |05 which pass through the slots 96 of link93 and 70 are screw threaded into a clamping ring |06 on the back oflever 93. An eccentric journal |01 passes through hub |02 for thereception of a pivot pin |08 mounted in a lug |09 on the rear face ofthe casting 43. 75

The link 88 is secured to a pen operating shaft ||2 by a collar ||3which is fixed in the opening ||4 in the end of said link. as bybrazing, welding. riveting or soldering. said collarbeing secured to thepen shaft ||2 by a set screw H8. 'Ihe pen shaft passes through a tubularhousing I which extends through the back wall of the casting 48 andintothe casing 44 in which the chart or dial and the pen are housed. Thetubular housing is screw threadedly engaged with casting 43 as at ||1,the end of said tubular housing within the casting 43 being closed by athreaded cap ||8 which makes a snug ilt with the pen shaft ||2 and theend of the tubular housing The 0pposite end of the tubular housing isenclosed by a wall |2| having a central opening through which thecentral shaft ||2 carrying the pen passes. The pen shaft ||2 has aslightly tapered conical portion |22 which bears against the annularflange |2|, and these engaging surfaces are ground and lapped in toprovide a tight and smooth joint at this point. A screw |23 normallycloses an opening in the tubular housing H8, through which lubricant maybe introduced into said tubular housing. As the end of the pen shaft ||2projects into the pressure chamber in casing 43, there is no opportunityfor the sealing grease in the tubular housing to escape along the shaftagainst this pressure, and the spring |6| and pressure in casing 43 urgethe conical end of the shaft H2 against the seat in wall |2| thus aidingin preventing escape of lubricant or pressure at this point. Thelubricant therefore forms a seal around shaft |2. By the structure justdescribed it will be seen that rotation of the pen link 88 will rotatepen shaft ||2 due to the sleeve ||3 secured to the two parts.

In order to take up any lost motion between the pin 82 carried by theoat arm and the pen operating link 98, said link has pivotally securedthereto a take-up link |23', pivoted at |24 to link 98. The links 88 and|23' are shown assembled in Figure 8 and link |23 is shown in detail inFigures 15 and 16. Link |23 has a portion |28 extending outwardly andparallel to slot 81, said portion having Vbeen leveled to substantiallya knife edge |28, to reduce friction. A pin |21 is secured to link |23'and passes through said link and into an opening |28 in link 88, saidopening being slightly larger than the pin |21 which enters saidopening, as seen in Figure 1. A spring |3| is secured at one end to pin|21 and is coiled around sleeve ||3 which pivotally supports link 98,and has its other end secured in opening |32 in link 98.

It will be seen from Figure 8 that the spring |3| tends to move thetake-up link |23' about its pivot |24 so that the knife edge |28 bearsconstantly against the pin 82 which is carriedby the float. arm. Sincethe opening |28 in link 88 is larger than the pin |21 the take-up link|23 has a limited motion with respect to link 98. By this constructionlost motion between link 98 and the pin 92 is automatically taken up atall times, and any wear between these parts is also automaticallycompensated for by the link |23. The resistance to the movement of thepen shaft ||2 and the parts movable therewith including the pen is verysmall, and the spring |3| is strong enough to move these parts withoutbending. Therefore motion of the pin 92 is directly transmitted withoutlost motion to the pen shaft ||2.

Since the outer link 83 pivots about the pin |98 and the hub |92 iseccentric to pin |98, it will be clear that by loosening the set screws|98, the dial 9| may be partially rotated to thus move the eccentric hub|92 about pin |88 as an axis. Such movement of hub |82 functions toeither decrease or increase the effective length of the link 83.

'This shortening or lengthening of link 83 is for 5 be made or themovements of the pen may be lengthened or shortened by simply looseningscrews |98 and rotating dial |9|. Indicating marks ||9 are provided ondial |9| and link 93 to aid in calibration. 20

The linkage as above described compensates for inaccuracies of movementbetween the float and the pen arm as follows. Referring to Figure 19since the pin 92 and the pivot |98 are a fixed distance apart, as thefloat rises from the position 25 shown in full lines, the pin 82 movesslightly to the left thereof, thus sliding in the slot 91 in' the penlink 98. Vertical movement of the pin 92, of course causes rotation ofthe pen link 98 to carry therewith the pen shaft 2. Since link 30 98 isproportionately shorter than link 83. during this movement the pin 92slides slightly in and out and to and from the pen shaft ||2, thuschanging the radius of action of the pin 92 about the shaft ||2 as anaxis. 35

The pin 92 takes the path A shown in Figure 19 and said pin contactswith lever 88 at point b when fthe float is down and the parts are inthe position shown in full lines. When the pin rises to the dotted lineposition it moves in path A 40 whereas point b moves in path B aboutshaft |2 as a center. When the parts reach the dotted line position pin82 contacts with lever 98 at point a, whereas point b, has moved to b.Therefore the effective leverage on link 98 changes as the iioat 45rises and fails.

By mathematical formula the proper length of the links and distancesbetween centers can be calculated to cause a rotation of pen shaft ||2in substantially equal arc units for equal vertical 50 movements of theiloat.

In some installations of orifice meters it has been found that there isa pulsating or fluttering in the pressures to such extent that theindicator hand or pen flutters. In order to overcome this 55 diiliculty,we have provided an improved dampening device to resist the iiow ofmercury in the U tube so that minor pulsations of pressure are nottransmitted to the pen shaft. This device is shown in Figure 1 and indetail in Figure 11. 60

'I'he tube 65 is slotted adjacent the lowest portion thereof and acombined dampening device and drain valve is secured over the bodyportion of said tube, preferably by welding, or soldering. 'I'he devicecomprises a casing |35 with a passage G5 |36 which communicates with theslot in the tube 85. The passage |36 is screw threaded at its oppositeend as at |31 and is adapted to receive a clamping collar |38. Collar|38 is centrally apertured to receive the projecting end |39 of thevalve |42, which valve includes the solid partition |43 which may beturned to various positions to provide an adjustable restriction in thevalve in set position and to retain packing around the valve stem toprevent leakage of the liquid. As shown in Figure 1l, the portion |43 ofthe valve |42 is completely open to provide the minimum 5 restriction ordampening eifect in the tube. By loosening thel threaded collar |38, thevalve |42 may be rotated to turn the partition |43 thereof into more orless restricted positions as regards passage |36. Thus a variablerestriction is provided in the tube connecting the high and low pressurechambers such that slight fluctuations in pressure are not transmittedto the indicating means such as the pen arm.

In order that the liquid contained within the tube may be convenientlydrained so that the meter may be shipped, the body |35 Ais provided witha passage |44 leading downwardly from passage |36 and communicating witha cross-channel |45. Thebody |35is bored and threaded to receive a plug|46 having a conical end |41 for cooperat' ing with a conical seat inthe cross-passage |45. A drain opening |48 communicates with thecrosschannel |45. If the needle valve |46 is rotated the conical end |41thereof leaves the seat provided in the end of the cross-channel |45 andthe liquid contained in the tube may drain through the passage |44,cross-channel |45, and out of the vent |48.

By the above described construction a simple unitary dampening deviceand drain valve is pro- -vided for use in orifice meters which issecurely fixed to the U tube to prevent the possibility of leakage..

A slight modification of the arrangement of the linkage is shown inFigure 9. Ordinarily the links will be so positioned that there will beno leakage between the conical end |22 of the pen shaft I2 an-d theinwardly projecting flange |2| of the stuiing box |l6. However, in orderto prevent any possible leakage at this point, a spring |6I is shown inFigure 9 which is clamped on the pin |08 by a collar |64 and has its endin engagement with the projecting end of the pen shaft ||2. This spring|6| maintains the conical portion |22 of the cam shaft ||2 intocloseengagement with its ground seat I2 so that there can be no leakage oflubricant at this point. In order to accommodate the spring 6| the link93 is moved outwardly beyond the fio'at arm 48.

In or-der to provide a simple and readily adjustable mounting for theorifice meter the casing 44 has a depending mounting bracket or strap|1| thereon formed to provide an annular ring I 12 at its lower end.Ringv |12 has a plurality of screw-threaded openings therein forthereception of correspondingly threaded locking bolts |13.

The pipe has mounted thereon -a- U-bolt |66 connecte-d to a bracket |61Awhich has its inner surface curved to iit the pipe A The bracket |61 isprovided with a screw-threaded opening in which is threaded one end of ashort pipe or rod |68. The ring |12 is fitted over pipe |68 and clampedthereto by bolts |13. A

65 In order to level the meter thebracket |61 is provided at oppositeends with adjusting screws |144 the lower ends of which engage the pipeI. f It will be apparent that our orifice meter may be easily andaccurately mounted in position.

After the bracket|61 is secured to the pipe the ring,T |12 may simply beslipped over the pipe |68, the meter adjusted -as to height, and thebolts |13 tightened. The instrumentv may then be l leveled bytheleveling screws |14.

It will of course be understood that the meter y 75 maybe mounted on anysupport other than the pipe' |the shape of bracket |61 being changedaccordingly. l

It is believed that the operation of th above described orifice meterwill be clear fr m the above description thereof. vWhen the `meter has 5been installed as shown in Figure 2 the filling plug 89 may be removedand the proper amount of liquid such as mercury poured into the tube 65.,When the valves 5 and 9 are open the low and high pressure are put uponthe pressure 10 chambers of the orice meter. In order to set or zero theinstrument the valves I8 and 22 are opened and I9 is close-d whereby thehigh and low pressure pipes 3 and4 are shunted around the instrumentsuch that the instrument should read 15 aero.v Ifit is desired to readthe pressure on either side of the oric'e this may be done by operationof valve I9, as previously described, a pressure gauge being screwedinto opening21 of manifold |6. 20

Due to the linkage provided between the float arm 48 and the indicatorpen shaft ||2,'said pen shaft moves equal distances for equal movementsof the oat arm in all positions thereof. This is due to the fact thatthe slot 91 in the link 98 25 allows the pin 92 of the float arm to moveback and forth with regard to the pen` shaft, thus shortening orlengthening the eifective radius 'of the arm 98. L

By loosening of set screws |05 .the dial |0| may 30 be rotated tomove'hub |02 about axis |06 to thereby change the effective length oflink 93 in order to calibrate instrument accurately and also in order toincrease or decrease the movement of the pen shaft for equal movementsof the float 35 arm. The take-up lever |23 automatically eliminates lostmotion between a pin 92 and the lever 98 connected to the pen shaft.

Although the compensating linkage has been described in detail inrelation to an orifice meter having a oat,'it will be clearly understoodthat our invention is not limited to orifice meters, since the samecompensating movement may be used in anyfloat gauge, or in fact in anymechanical movement wherein reciprocatory motion is to be converted intorotary motion with accuracy. l

The invention may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. The presentembodiment is therefore to be considered in all respects as illustrativeand not restrictive, the scope of the invention being, indicated by theappended claims rather than by the foregoing description, and allchanges which come within the meaning and range of equivalency of theclaims are therefore intended to be embraced therein.

What we claim and desire to secure by United States Letters Patent is:

1. In an orice meter, a low pressure chamber, a U tube connectedthereto,la oat in said chamber, a rod' secured to the lower` portion ofsaid float and extending downwardly into said tube, a valve looselypivoted to said rod and within said tube, and a valve seat within saidtube for receiving said valve whereby said valve will accurately engagesaid seat to prevent loss of liquid in said U tubewhen excessivepressureis applied' to said chamber.

2. The invention asin claim 1 wherein said valve has a guide rod thereonextending downwardly into said tube, and a guide through which. saidrrodpasses for `guiding said rod, valve, and

float.

3. An orifice meter having a high pressure chamber, a low pressurechamber, a U tube connecting said chambers, in combination with acombined dampening device and drain -yalve comprisinga casing flxedlysecured to the bottom of said U tube, a channel in said casing incommunication with said tube, a rotatably adjustable plug in saidchannel, there being a vent in said casing communicating with saidchannel 10 in the vicinity of said plug for preventing accumulation ofsediment about the-plug, and a valve independent of said plug for'closing said vent. y

\ 4. In sub-combination in a differential gauge,

a main casting having high pressure .and low pressure passages therein,a' float chamber detachably secured thereto in communication with one ofsaid passages, a pressure chamber detachably secured to the casting incommunication with the other of said passages, a sleeve detachablysecured to one of said chambers and having a valve stem guide therein, avalve seat member clamped between said sleeve and the chamber to whichit is secured, a valve secured to the float and seated therein, and aU-tube for holding liquid welded to the high pressure chamber and to thesleeve.

5. In sub-combination in a differential pressure gauge, a pressureresponsive unit containing a columnof liquid, connections fortransmitting high and low pressures to the respective ends of saidcolumn and including means forming a passageway between the low pressureconnection and the respective end of said liquid column, a float havinga float rod extending through the passageway, a pressure operatedautomatic valve assembly comprising a composition seat fitted at thatend of the passageway adjacent the low pressure connection, and asealing element on the float designed to seat thereagainst when thepressure differential reaches a given maximum.

6. The invention defined in claim 5 wherein said sealing element isconvex. v 7. -In combination with a differential pressure responsivedevice, a unitary valve body portion, a pipe secured to said bodyportion intermediate its j ends and adapted to be connected at one endwith said device, a second pipe integrally connected to said bodyportion and connected at one end to said device, said valve body havinga passage therethrough communicating between said pipes, a cross passagethrough said body communicati ing with said first passage, a valve forcontrolling said cross passage, and valves adjacent the ends of saidfirst passage for controlling flow therethrough.v `8. In a differentialgauge, a main casting having high and low pressure passages therein, afloat chamber detachably secured thereto in communication with one ofsaid passages, a pressure chamber detachably secured to said casting incommunication with the other of said passages, a sleeve detachablysecured to one of said chambers and having a valve stem guide therein, anonmetallic resilient valve seat member clamped between said sleeve andthe chamber to which it is secured, a valve adapted to be seatedtherein, and a U-tube for holding liquid secured to the pressure chamberand to said sleeve. 9. In an orifice meter, a casing having a pressurechamber therein, an actuating mechanism in /said casing, a hollowtubular housing secured to the casing with its .inner end opening intosaid chamber, and providing bearings at its ends, a

ing and rotatably supported in said bearings, and means for introducingsealing lubricant in said housing surrounding said pen shaft wherebysaid lubricant serves to seal said housing against passage of fluid fromsaid chamber. 5

10. In an orifice meter, a casing having a pressure chamber therein, anactuating mechanism in said casing, a hollow tubular housing secured tothel casing and opening into said chamber, bearings adjacent the ends ofthe housing, a pen 10 shaft extending through said housing and throughsaid bearings, said pen shaft having a conical shoulder acting againstone of said bearings, and means for introducing lubricant into saidhousing surrounding said shaft to seal said 15 housing against passageof fluid therethrough.

11. In an orifice meter, a casing having a pressure cha'mber therein, anactuating mechanism in said casing, a hollow tubular housing secured tokthe casing with its inner end opening into said 20 chamber andproviding a bearing at its inner end, the outer end of said housinghaving an inwardly extending annnular flange, a pen shaft projectingthrough saidl tubular housing and through said bearing into saidchamber, said pen shaft 25 having a conical shoulder adjacent its outerend terminating in a reduced portion which projects throughv saidflange, and means for introducing sealing lubricant in said housingsurrounding said pen shaft whereby said lubricant serves to seal 30 saidhousing against passage of fluid from said chamber.

12. In an orifice meter, a casing having a pressure chamber therein, anactuating mechanism in said casing, a hollow tubular housing secured to35 the casing with its inner end opening into said chamber, a cap forclosing the inner end of said housing and providing a bearing therein,the other end of said housing having an inwardly extending annularflange, a pen shaft projecting o through said tubular housing andbearing into said chamber and having a conical shoulder adjacent itsouter end terminating in a reduced portion which projects through saidflange, and means for introducing sealing lubricant into said 5 housingsurrounding said pen shaft whereby said lubricant serves to seal saidhousing against passage of'uid from said chamber.

13. In an orifice meter, a casing having a pressure chamber therein, anactuating mechanism in 50 said casing, a hollow tubular housing securedto said casing with its inner end opening into said chamber, a shaftbearing at one end of said housing, av threaded member providing aibearing threadedly' secured in and sealed against the 55 other end ofsaid housing, a pen shaft projecting through said tubular housing androtatably supported in said bearings, and means for introducing sealinglubricant in said housing surrounding said pen shaft, whereby saidlubricant serves to 00 seal said housing against passage of uid fromsaid chamber,

14. In an o'rice meter, a casing having a pressure chamber therein, anactuating mechanism in said casing, a hollow tubular housing secured to55 the casing with its inner end opening into said chamber and providinga bearing at itslinner end, the outer end of. said housing having aninwardly extending annularanga a pe'n shaft projecting through saidtubular housing and through said 70 bearing into said chamber, said penshaft having a conical shoulder adjacent.its outer end terminating in areduced portion which projects through said flange, a spring acting onsaid pen shaft to hold said conical shoulder against said flange andmeans for introducing a sealing lubricant in said housing surroundingsaid pen shaft, whereby said lubricant serves to seal said housingagainst passage of fluid from said chamber.

15. In a diiTerential gauge, a main casting having high pressure and lowpressure passages therein, a oat chamber detachably secured thereto incommunication with one of said passages, a pen shaft, a float in saidchamber for operating said pen shaft, a pressure chamber detachablysecured to the casting in communication with the other of said passages,a U-tube for holding liquid, secured to said pressure chamber, meansdetachably securing said U-tube to said pressure chamber, a valve seatmember clamped between said U-tube and the float chamber, and a valvearticulately connected to said iloat and depending therefrom and adaptedto be seated on said valve seat member when the float reaches its lowerposition.

16. In combination With a differential pressure responsive device, aunitary valve body portion, a pipe integrally secured to said bodyportion between its ends and adapted to be connect-ed at one end to saiddevice, a second pipe integrally connected to said body portion andadapted to be connected at one end with said device, said valve bodyhaving a passage therethrough and in communication with said pipes,valves in said passageway adjacent each end thereof controllingcommunication of. said passageway with said pipes, an opening in saidbody between said valves, and a valve for placing said passageway incommunication with said opening.

17. The combination with a differential pressure responsive device of aunitary manifold structure comprising a unitary valve body having apassage therethrough, a low pressure pipe integrally secured to saidvalve body between its ends and communicating with said passageway, 10 ahigh pressure pipe integrally secured to said valve body at one end forcommunication with said passage, said low pressure pipe extending fromsaid manifold for connection with said pressure responsive device and inthe opposite direction for connection with a source of pressure, saidhigh pressure pipe incuding a branch for connection to said pressureresponsive device, the integral connections of said pipes to said valvebody serving to approximately locate said pipes in position for makingsaid connections, and valves in said body adjacent each end thereof forcontrolling communication of said passage with said pipes, an opening insaid body between said valves, and a valve for placing said passagewayin communication with said opening.

WALTER H. PARKER. NELSON J. SEIBERT. ALLEN D. MACLEAN.

